TRAILMOBILE CAMPAIGN NO.TRAILER.SEPT.1, 1955 THRU JUNE 1 5, 1971.POSSIBILITY THAT DESIGN OF "P" AUTOMATIC FIFTH WHEELDOES NOT PROVIDE POSITIVEMEANS FOR LOCKING HANDLE WHEN KINGPIN LOCKING JAWS ARE ACTIVATED.IFCONDITION EXISTS, THERE ISNO ASSURANCE THAT LOCKING JAWS STAY IN LOCKEDPOSITION TIME T HE TRAILER IS COUPLED AND IN OVER-THE-ROAD OPERATION.UNDER EXTREME CONDITIONS IT IS POSSIBLE FOR TRAILER TO FOR TRAILER TOBECOMEACCIDENTALLY DISENGAGED FROM TRACTOR.(CORRECT BY INS PECTING AND PROVIDINGLOCKING MECHANISM WHERE NECESSARY.)